This page has a list of various acme screws. http://www.nookindustries.com/acme/AcmeAvailability.cfm
It has a column showing "torque to raise 1 lb". If multiply that column by the number of lbs force you need it will give you the torque required in in-lbs. Divide that by 16 to get in-oz. You do need to be aware that starting torque will probably be less than the 59oz holding torque. Also, for all steppers, torque drops as rpms increase. The only way to know is to look at the torque curves for your motor.